On a large cutting board, position your chef's knife on its side and press the heel of the blade to crush each cucumber piece until it cracks in the center, splits in half or splinters completely into pieces.
In a medium bowl, toss the cucumbers with the salt, transfer to a colander, and let sit in the sink to drain, about 30 minutes. Meanwhile, in the same bowl, add the vinegar and garlic and set aside.
After 30 minutes, add the sesame oil, gochugaru, fish sauce and sugar to the bowl with the vinegar and garlic, and whisk to combine.
Use a paper or cloth kitchen towel to pat the cucumbers dry, then add the cucumbers to the dressing and toss until well coated.
Garnish with the optional herbs before serving. This is best eaten right away, but can be refrigerated for up to 24 hours.
1 pound cucumbers cut into 1-inch pieces on the bias
1 teaspoon kosher salt
2 tablespoons white distilled vinegar
1/2 teaspoon finely grated garlic
1 tablespoon plus 1 teaspoon sesame oil
1 tablespoon gochugaru
2 teaspoons fish sauce
1 teaspoon granulated sugar
Coarsely chopped chives, thinly sliced scallions, or cilantro or flat-leaf parsley leaves for garnish (optional)